Fix -Wredundant-constraints (#4044)

* Fix -Wredundant-constraints

* Fixes

---------

Co-authored-by: Michael Peyton Jones <me@michaelpj.com>

Author: jhrcek

hls-graph/src/Development/IDE/Graph/Internal/Types.hs

@@ -110,7 +110,7 @@ keyMap = unsafePerformIO $ newIORef (GlobalKeyValueMap Map.empty IM.empty 0)
 
 {-# NOINLINE keyMap #-}
 
-newKey :: (Eq a, Typeable a, Hashable a, Show a) => a -> Key
+newKey :: (Typeable a, Hashable a, Show a) => a -> Key
 newKey k = unsafePerformIO $ do
   let !newKey = KeyValue k (T.pack (show k))
   atomicModifyIORef' keyMap $ \km@(GlobalKeyValueMap hm im n) ->

plugins/hls-alternate-number-format-plugin/src/Ide/Plugin/Conversion.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP          #-}
 {-# LANGUAGE ViewPatterns #-}
 module Ide.Plugin.Conversion (
     alternateFormat
@@ -158,19 +159,21 @@ toBase conv header n
   | n < 0 = '-' : header <> upper (conv (abs n) "")
   | otherwise = header <> upper (conv n "")
 
-toOctal :: (Integral a, Show a) => a -> String
-toOctal = toBase showOct "0o"
-
-toDecimal :: Integral a => a -> String
-toDecimal = toBase showInt ""
+#if MIN_VERSION_base(4,17,0)
+toOctal, toDecimal, toBinary, toHex :: Integral a => a -> String
+#else
+toOctal, toDecimal, toBinary, toHex:: (Integral a, Show a) => a -> String
+#endif
 
-toBinary :: (Integral a, Show a) => a -> String
 toBinary = toBase showBin_ "0b"
   where
-    -- this is not defined in versions of Base < 4.16-ish
+    -- this is not defined in base < 4.16
     showBin_ = showIntAtBase 2 intToDigit
 
-toHex :: (Integral a, Show a) => a  -> String
+toOctal = toBase showOct "0o"
+
+toDecimal = toBase showInt ""
+
 toHex = toBase showHex "0x"
 
 toFloatDecimal :: RealFloat a => a -> String

plugins/hls-alternate-number-format-plugin/src/Ide/Plugin/Literals.hs

@@ -15,8 +15,7 @@ import qualified Data.Text.Encoding            as T
 #endif
 import           Development.IDE.GHC.Compat    hiding (getSrcSpan)
 import           Development.IDE.Graph.Classes (NFData (rnf))
-import           Generics.SYB                  (Data, Typeable, everything,
-                                                extQ)
+import           Generics.SYB                  (Data, everything, extQ)
 import qualified GHC.Generics                  as GHC
 
 -- data type to capture what type of literal we are dealing with
@@ -49,7 +48,7 @@ getSrcSpan = \case
     FracLiteral ss _ _ -> unLit ss
 
 -- | Find all literals in a Parsed Source File
-collectLiterals :: (Data ast, Typeable ast) => ast -> [Literal]
+collectLiterals :: Data ast => ast -> [Literal]
 collectLiterals = everything (<>) (maybeToList . (const Nothing `extQ` getLiteral `extQ` getPattern))
 
 

plugins/hls-alternate-number-format-plugin/test/Properties/Conversion.hs

@@ -15,28 +15,28 @@ conversions = testGroup "Conversions" $
     ]
     <>
     map (uncurry testProperty)
-    [ ("Match HexFloat", prop_regexMatchesHexFloat @Double)
+    [ ("Match HexFloat", prop_regexMatchesHexFloat)
     , ("Match FloatDecimal", prop_regexMatchesFloatDecimal)
     , ("Match FloatExpDecimal", prop_regexMatchesFloatExpDecimal)
     ]
 
 prop_regexMatchesNumDecimal :: Integer -> Bool
 prop_regexMatchesNumDecimal = (=~ numDecimalRegex) . toFloatExpDecimal @Double . fromInteger
 
-prop_regexMatchesHex :: (Integral a, Show a) => a -> Bool
+prop_regexMatchesHex :: Integer -> Bool
 prop_regexMatchesHex = (=~ hexRegex ) . toHex
 
-prop_regexMatchesOctal :: (Integral a, Show a) => a -> Bool
+prop_regexMatchesOctal :: Integer -> Bool
 prop_regexMatchesOctal = (=~ octalRegex) . toOctal
 
-prop_regexMatchesBinary :: (Integral a, Show a) => a -> Bool
+prop_regexMatchesBinary :: Integer -> Bool
 prop_regexMatchesBinary = (=~ binaryRegex) . toBinary
 
-prop_regexMatchesHexFloat :: (RealFloat a) =>  a -> Bool
+prop_regexMatchesHexFloat :: Double -> Bool
 prop_regexMatchesHexFloat = (=~ hexFloatRegex) . toHexFloat
 
-prop_regexMatchesFloatDecimal :: (RealFloat a) =>  a -> Bool
+prop_regexMatchesFloatDecimal :: Double -> Bool
 prop_regexMatchesFloatDecimal = (=~ decimalRegex ) . toFloatDecimal
 
-prop_regexMatchesFloatExpDecimal :: (RealFloat a) =>  a -> Bool
+prop_regexMatchesFloatExpDecimal :: Double -> Bool
 prop_regexMatchesFloatExpDecimal = (=~ numDecimalRegex ) . toFloatExpDecimal

plugins/hls-call-hierarchy-plugin/src/Ide/Plugin/CallHierarchy/Internal.hs

@@ -243,8 +243,8 @@ mkCallHierarchyCall mk v@Vertex{..} = do
                     []     -> pure Nothing
 
 -- | Unified queries include incoming calls and outgoing calls.
-queryCalls :: (Show a)
-    => CallHierarchyItem
+queryCalls ::
+    CallHierarchyItem
     -> (HieDb -> Symbol -> IO [Vertex])
     -> (Vertex -> Action (Maybe a))
     -> ([a] -> [a])

plugins/hls-change-type-signature-plugin/src/Ide/Plugin/ChangeTypeSignature.hs

@@ -70,15 +70,12 @@ data ChangeSignature = ChangeSignature {
                          , diagnostic  :: Diagnostic
                          }
 
--- | Constraint needed to trackdown OccNames in signatures
-type SigName = (HasOccName (IdP GhcPs))
-
 -- | Create a CodeAction from a Diagnostic
-generateAction :: SigName => PluginId -> Uri -> [LHsDecl GhcPs] -> Diagnostic -> Maybe (Command |? CodeAction)
+generateAction :: PluginId -> Uri -> [LHsDecl GhcPs] -> Diagnostic -> Maybe (Command |? CodeAction)
 generateAction plId uri decls diag = changeSigToCodeAction plId uri <$> diagnosticToChangeSig decls diag
 
 -- | Convert a diagnostic into a ChangeSignature and add the proper SrcSpan
-diagnosticToChangeSig :: SigName => [LHsDecl GhcPs] -> Diagnostic -> Maybe ChangeSignature
+diagnosticToChangeSig :: [LHsDecl GhcPs] -> Diagnostic -> Maybe ChangeSignature
 diagnosticToChangeSig decls diagnostic = do
     -- regex match on the GHC Error Message
     (expectedType, actualType, declName) <- matchingDiagnostic diagnostic
@@ -107,7 +104,7 @@ errorMessageRegexes = [ -- be sure to add new Error Messages Regexes at the bott
 
 -- | Given a String with the name of a declaration, GHC's "Expected Type", find the declaration that matches
 -- both the name given and the Expected Type, and return the type signature location
-findSigLocOfStringDecl :: SigName => [LHsDecl GhcPs] -> ExpectedSig -> String -> Maybe RealSrcSpan
+findSigLocOfStringDecl :: [LHsDecl GhcPs] -> ExpectedSig -> String -> Maybe RealSrcSpan
 findSigLocOfStringDecl decls expectedType declName = something (const Nothing `extQ` findSig `extQ` findLocalSig) decls
     where
         -- search for Top Level Signatures

plugins/hls-eval-plugin/src/Ide/Plugin/Eval/Parse/Comments.hs

@@ -301,7 +301,7 @@ blockProp = do
     AProp ran prop <$> resultBlockP
 
 withRange ::
-    (TraversableStream s, Stream s, Monad m, Ord v, Traversable t) =>
+    (TraversableStream s, Ord v, Traversable t) =>
     ParsecT v s m (t (a, Position)) ->
     ParsecT v s m (Range, t a)
 withRange p = do
@@ -489,7 +489,7 @@ consume style =
         Line     -> (,) <$> takeRest <*> getPosition
         Block {} -> manyTill_ anySingle (getPosition <* eob)
 
-getPosition :: (Monad m, Ord v, TraversableStream s) => ParsecT v s m Position
+getPosition :: (Ord v, TraversableStream s) => ParsecT v s m Position
 getPosition = sourcePosToPosition <$> getSourcePos
 
 -- | Parses example test line.

plugins/hls-overloaded-record-dot-plugin/src/Ide/Plugin/OverloadedRecordDot.hs

@@ -50,10 +50,9 @@ import           Development.IDE.GHC.Compat           (Extension (OverloadedReco
                                                        GhcPass,
                                                        HsExpansion (HsExpanded),
                                                        HsExpr (HsApp, HsVar, OpApp, XExpr),
-                                                       LHsExpr, Outputable,
-                                                       Pass (..), appPrec,
-                                                       dollarName, getLoc,
-                                                       hs_valds,
+                                                       LHsExpr, Pass (..),
+                                                       appPrec, dollarName,
+                                                       getLoc, hs_valds,
                                                        parenthesizeHsExpr,
                                                        pattern RealSrcSpan,
                                                        unLoc)
@@ -264,9 +263,7 @@ convertRecordSelectors RecordSelectorExpr{..} =
 -- |Converts a record selector expression into record dot syntax, currently we
 -- are using printOutputable to do it. We are also letting GHC decide when to
 -- parenthesize the record expression
-convertRecSel :: Outputable (LHsExpr (GhcPass 'Renamed))
-                    => LHsExpr (GhcPass 'Renamed)
-                    -> LHsExpr (GhcPass 'Renamed) -> Text
+convertRecSel :: LHsExpr (GhcPass 'Renamed) -> LHsExpr (GhcPass 'Renamed) -> Text
 convertRecSel se re = printOutputable (parenthesizeHsExpr appPrec re) <> "."
                         <> printOutputable se
 

plugins/hls-refactor-plugin/src/Development/IDE/GHC/Dump.hs

@@ -13,7 +13,7 @@ import           GHC.Plugins                           hiding (AnnLet)
 import           Prelude                               hiding ((<>))
 
 -- | Show a GHC syntax tree in HTML.
-showAstDataHtml :: (Data a, ExactPrint a, Outputable a) => a -> SDoc
+showAstDataHtml :: (Data a, ExactPrint a) => a -> SDoc
 showAstDataHtml a0 = html $
     header $$
     body (tag' [("id",text (show @String "myUL"))] "ul" $ vcat
@@ -244,8 +244,7 @@ showAstDataHtml a0 = html $
             annotationEpaLocation :: EpAnn EpaLocation -> SDoc
             annotationEpaLocation = annotation' (text "EpAnn EpaLocation")
 
-            annotation' :: forall a .(Data a, Typeable a)
-                       => SDoc -> EpAnn a -> SDoc
+            annotation' :: forall a. Data a => SDoc -> EpAnn a -> SDoc
             annotation' tag anns = nested (text $ showConstr (toConstr anns))
               (vcat (map li $ gmapQ showAstDataHtml' anns))
 
@@ -266,16 +265,16 @@ showAstDataHtml a0 = html $
             srcSpanAnnN :: SrcSpanAnn' (EpAnn NameAnn) -> SDoc
             srcSpanAnnN = locatedAnn'' (text "SrcSpanAnnN")
 
-            locatedAnn'' :: forall a. (Typeable a, Data a)
+            locatedAnn'' :: forall a. Data a
               => SDoc -> SrcSpanAnn' a -> SDoc
             locatedAnn'' tag ss =
               case cast ss of
                 Just ((SrcSpanAnn ann s) :: SrcSpanAnn' a) ->
-                      nested "SrcSpanAnn" $ (
+                      nested "SrcSpanAnn" (
                                  li(showAstDataHtml' ann)
                               $$ li(srcSpan s))
                 Nothing -> text "locatedAnn:unmatched" <+> tag
-                           <+> (text (showConstr (toConstr ss)))
+                           <+> text (showConstr (toConstr ss))
 
 
 normalize_newlines :: String -> String

plugins/hls-refactor-plugin/src/Development/IDE/GHC/ExactPrint.hs

@@ -258,7 +258,7 @@ needsParensSpace _               = mempty
 -}
 graft' ::
     forall ast a l.
-    (Data a, Typeable l, ASTElement l ast) =>
+    (Data a, ASTElement l ast) =>
     -- | Do we need to insert a space before this grafting? In do blocks, the
     -- answer is no, or we will break layout. But in function applications,
     -- the answer is yes, or the function call won't get its argument. Yikes!
@@ -348,7 +348,7 @@ graftExprWithM dst trans = Graft $ \dflags a -> do
 
 graftWithM ::
     forall ast m a l.
-    (Fail.MonadFail m, Data a, Typeable l, ASTElement l ast) =>
+    (Fail.MonadFail m, Data a, ASTElement l ast) =>
     SrcSpan ->
     (LocatedAn l ast -> TransformT m (Maybe (LocatedAn l ast))) ->
     Graft m a
@@ -643,7 +643,7 @@ instance ASTElement NameAnn RdrName where
 
 -- | Given an 'LHSExpr', compute its exactprint annotations.
 --   Note that this function will throw away any existing annotations (and format)
-annotate :: (ASTElement l ast, Outputable l)
+annotate :: ASTElement l ast
     => DynFlags -> Bool -> LocatedAn l ast -> TransformT (Either String) (LocatedAn l ast)
 annotate dflags needs_space ast = do
     uniq <- show <$> uniqueSrcSpanT